Jorge Lorenzo was very excited after closing the gap on championship leader Marc Marquez with a win at Phillip Island.

Getty Images: Quinn Rooney

Spaniard Jorge Lorenzo kept alive the race for the world championship with victory in a controversial Australian MotoGP at Phillip Island on Sunday.

The Yamaha rider pulled to within 18 points of Marc Marquez at the top of the championship with two races left after Marquez was sensationally black-flagged for ignoring a mandatory pit stop in the middle stages of the race.

The Australian MotoGP was shortened to 19 laps from a scheduled 26 laps amid safety concerns over Bridgestone tyres degrading on the new tarmac surface at the Phillip Island track.

Riders were required to make a mandatory pit stop by the 10th lap of the race and change to a replacement machine.

Marquez instead stayed on the track on his Repsol Honda for an extra lap and incurred a black flag from race officials. He was forced to re-pit, where he left the race.

That enabled Lorenzo to make up a maximum 25 points and keep alive the world title race.

"Today was a crazy race and much different than a normal race with the change of bikes in the middle of the race," said Lorenzo.

"Twenty five points, the best result possible, and we now have opened the world championship, but it is still very tough.

"Let's see what happens in Motegi."

Marquez led Lorenzo by 43 points coming into the Phillip Island race and would have become the youngest ever MotoGP champion if he had managed to outscore Lorenzo by eight points.

Marquez's Repsol Honda teammate Dani Pedrosa was second, 6.936sec adrift of Lorenzo, with Yamaha's Valentino Rossi making the podium in third place.